Heard Island 53 deg. 05 min. S., 73 deg. 30 min. E. Field area covered: southeast end of island from Long Beach to Gilchrist Beach. 150 GPS control points collected on 1986-1987 airphotos, using handheld GPS unit. To be used for a vegetation mapping project in progress for mapping of Heard Island vegetation communities, along with vegetation quadrat data covering ... major plant communities of the island. Vegetation quadrat data collected on monitoring sites set up in 1987 to record changes in vegetation, especially the grass Poa annua. Fixed photo-points re-photographed to record aspects of vegetation and glacier-front changes over 12 years. Heard Island environments are changing steadily as global climate change occurs. This project gathered information that will enable completion of a vegetation map for Heard Island; revisited sites studied and marked in 1987 to document changes in vegetation, including colonisation of recently deglaciated land; and provided advice for visitor management protocols to minimise vegetation disturbance. The parts of the island visited were surveyed for new species that may be recently arrived or previously unrecorded, and changes in species which had limited distribution in 1987 were documented.

2003-04 fieldwork undertaken

The fieldwork provides strong evidence of vegetation and habitat changes over the past 16 years, and a sound basis for future monitoring in a dynamic environment sensitive to global change. Work included documentation of 200 photopoints, mapping of limited-distribution plant species, and ground-checking of vegetation mapping from 1987. A solid baseline of 1987 data (photopoints, fixed transects) was remeasured. A new vascular plant species was recorded, Leptinella plumosa, increasing the vascular species list to 12. Differential GPS allowed precise documentation of 200 mapping control points for AADC and accurate locations of all photopoints, species mapping and fixed transects.

Descriptions of data collected for each JJS Data dictionary feature, and additional attributes, are included in metadata notes (word docs) accompanying the DGPS data.

The data associated with this metadata record are as follows:

a) Differential GPS data. The DGPS data in (b) and (c) below originate from these data.

Control points were collected in 2000 (between Gilchrist beach, Spit, Long Beach and Cape Gazert) and in 2003-04 (between Compton Lagoon, Spit and Long Beach, and Laurens Peninsula/Atlas Cove area) using Garmin Etrex hand-held GPS units.

Differential GPS data

Positional data were collected from areas between Long Beach and Compton Lagoon ... Spit (Heard Island) using Global Positioning System (GPS) equipment (Trimble GeoXT CE series handheld GPS units) and standard observational techniques. The collection of positional data were undertaken between 31-12-2003 and 21-2-2004.

The GeoXT units are mapping grade, single frequency receivers capable of decimetre accuracies over short baselines (less than 5 km). GPS data were collected by Jenny Scott (JJS), Robb Clifton (RC) and Justine Shaw (JDS). Between the 30-12-2003 and 21-2-2004 a Trimble ProXR receiver operating as a base station was used. At Heard Island, the receiver was located beside a Geoscience Australia receiver set up at the AUS094 survey mark, Spit Bay Camp. The survey mark is situated on a rock stack behind the base camp at 10.869 m asl. The baseline distance between the mobile receivers at the Sooty Valley field site and Spit Bay camp was less than 5 km. The base station logged data at 5 second intervals.

Post processing of the GeoXT data were achieved using Trimble GPS Pathfinder Office (2002). Results from GPS processing were exported to shapefile format. Each datafile is represented in two forms. Files with the extension SSF (standard storage format) have been downloaded from the GPS unit. All SSF files are data files and are stored in the latitude/longitude coordinate system, using the WGS84 horizontal datum. Files with the extension COR are corrected data files (SSF). COR files are the end product of differential correction of SSF files in GPS Pathfinder Office 2.90, Trimble Navigation Limited.

A data dictionary was set up (PAMT) using the SCAR Feature Catalogue (refer to link below) and GPS Pathfinder (r) Office 2.90, Trimble Navigation Limited. This Data dictionary is called JJS.ddf (JJS_1.txt) and includes the following features: Points: Control NEW, Control OLD, Photo, Quadrat, Other, Site Record. Lines: Transect, Other. Areas: Veg area, Other. Additional attributes for these features have been added to each record (both in the .ssf files and the final corrected data) and are described below.

Some attributes were added to the corrected control point data. The point locations have been pinpointed and marked on hardcopies of the 1987 aerial imagery and 2003 satellite imagery held by the AADC.

The control point data collected using the Trimble GeoXT CE series GPS units are available for downloading (refer to link below). Included are the uncorrected Trimble files, the differentially corrected Trimble files, the differentially corrected control points in shapefile format and some additional metadata.

Some additional control point data collected at the western end of Heard Island between December 2003 and February 2004 using handheld Garmin Etrex GPS receivers are also available for download (refer to link below). Values provided in temporal coverage are approximate only.

Access Constraints
These data are publicly available for download at the provided URL.